Pneumatic hammer.



PATENTED OCT. 80, 1906.

I No. 884,641.

U. PRUNER.

PNEUMATIC HAMMER. 2 sums-sum 1.

APPLICATION FILED DEG. 29, 1903. M y

No. 834,641. y PATENTED OCT. so, 1906.

G.PRUNBR. PNEUMATIC HAMMER.

APPLICATION FILED 13110.29, 1903.

2 SHEETS-SHEET 2.

IIIIIIIIIIII filirjllarrwy TED STATES ooNRAn, PRUNER, or

PATENT orrron.

WIENER-NEUSTADT, AUSTRIA-HUNGARY.

PNEUMATIC HAMMER.

substitute for a steam-hammer to effect the same purpose with a small weight of hammer-ram, hut operating with considerable. pressure, there being a device for regulating pressure, thereby the force of the blow, and also a step-hy-step device for rais-.

ing the hammer ram and holding, it in the uplifted position. I

The improved pneumatic hammer is illustrated in the accompanying drawings, in which Figure 1 is a side view, Fig. 2 a front view, and Fig. 3 a plan view, of the hammer. Fig. 4 is a longitudinal section throu h the two cylinders with their fittings. Fig. 5 illustrates a longitudinal section through an air-discharge valve. Fig. 6 is a vertical section, Fig. 7 a horizontal section, and Fig. 8 a plan view, of the'gearing-cock. Figs. 9 and 5.0 show, in the same views as 8, two different positions of the cock-plug. Figs. 11 to 13 show another modificatlon of the gearing-eock with two plugs, of which Fig. 11're resentsa vertical section through the cool:

the parts being in that position when the hammer works with full pressure. Fig. 12 is a vertical cross section on the line A A' of Fig. 11, the farts being in that osition when the hammer is out of action. i 13 is a similar section like Fig. 1 1, showingiilie parts in that position when the hammer works with halfpressure,

The hammer consists of a vertical cylinder 1, fitted wlth a ram-piston 2, and an airpump cylinder 3, fitted with the pump-piston 6, which are mounted together on a suitable The cylinders 1 and 3 of the airframe. pump and hammer are in conneotionwith each other on both sides of the pistons by means of pipes 17 and 19. The pump-cylinder3 is provided at a suitable point in its length with an intermittently-opened airsupply organ 11, which in its simplest form consists merely of a non-return valve open- Specification of Letters E'atent. "Application filed December 29, 1903.- Serial Ho. 187.056.

Patented Get. 30, 1906.

ing inward, (see Fig. 4,) through which on the movement of the piston" 6 air is drawn in alternately on each side of this latter. This valve 11 is so arranged that the passage from this valve is closed by the air-pump piston 6 when theram-piston 2 begins its upward-stroke, so that when. the ram-piston 2 ascends it is not able to draw air through the valve The inflow of air will chiefly occur when the pump-piston 6, travelin away from the corresponding end of its cy der 3, I

has passed themouth of'the valve-passage. 1

The best situation of the valve 11 is at or about the middle of the stroke of the pumppiston 6, so that air canalso be drawn in on its other side on the return stroke and main tain on the average atmos heric pressure above the ram-piston 2. interposed .be-

tween the rower end 4 ofthe hammer-c lin-' der 1 and the corresponding end 25' or the' cylinder 3 of the air-pum is'a turn-cock 24', (see Figs. 6'to 10,) the s ell 26 of which is provided with a number of release-orifices 27, v

which on the closing of the plug 24 come successively into communication with the bore 28 of the plug 24 in such a way that the more the passage 19 from one cylinder 3 to i the other, 1, is throttled the more open will be the escape to the atmosphere. According, therefore, to. the position of the lug 24 of the turn-cock either the whole vo umeof air forced out of the air-pump 3 6 will pass to the hammer-cylinder 1, in which case the hammer will operate with its full stroke and fall, (see Figs. Sand 7,) or only a portion of the air will enter the hammer-cylinder}, the

remainder escaping into the orifices 27, in.

which case-the stroke and fall will be correspondingly reduced. (See Fig. 10-.) The passage 19 from cylinder 3 to cylinder 1 ma e entirel the air will although the pum -piston 6 is operated the hammer-ram 2 W11 remain at'rest. Ii the lug 24 is entirely closed, the air coming om the air-pumps enters the bore 28 of the plug 24 by an orifice or orifices 29.

cylinder 3 to cylinder 1, governed by the turn-cock 24, above described, an additional communication 20 is provided, containing a non-return valve 21, which opens toward the hammer-cylinder 1, the pu ose of which is to enable the ram 2 to be li ted step by step as follows: I

closed, (see Fig. 9,) and then ah. escape to the orifices 27, so that,

IOO

Inaddition to the direct passage 19' from If the turn-cock 24 is so placed that only a I 2, raising it step by step, and when it has reached 1ts highest positionit will be there maintained by; continued pumping. The

pipe communicates at its ends with the cylinders 1 and 3 at points adjacent to the bottom of the c inders'i. 4a., just below the lowest points 0 movement of the pistons.

To facilitate the steady ascent ofthe ram and avoid fluctuations, it will be advisable to get rid of the pressure on the upper surface of the piston 2 by fitting a mechanically-operated escape-valve 30, which can be either a lift-valve, a turn-cock, a screw-down valve, a slide-valve, or, preferably, may take the form of a ball-valve 30, (see Fig. 5,) ressed onto its seat by a strong spring 31. l ly means of a lever-and-link mechanism 32 3 3 23 22 and the rod 34 this valve is connected to the turn-cock 24, above mentioned, controlling the passage 19 to the under side of the ramcylinder .1 in such a way that if the latter is open the former is closed, and when the turncock 24 is closed the escape from above the ram-piston willbe freely open.

The employment of a spring-loaded valve 30 has the advantage that when the pump-:

piston and hammer are in rapid action an undue-pressure will be avoided by lifting the valve. I

Instead of employing the turn-cock above described a valve may be used, and instead of a series of openings 27 a second turn-cock (see Figs. 11'to 13) may be fitted, the plug 35 of which is in mechanical connection with that of the formeras, for instance, by means of toothed sectors 38 or levers and links. I

The steady ascent of the ram-piston may be effected by inserting an ordinary stopcock the passage 19 tothe under side of the ram and providing above and below the iston of the latter escape valves or cocks. o adjust the degree of opening, it will be advanta cons to provide a notched quadrant 36 an a lever 32, carrying a pawl 37, adapt- ,ed to engage with the notches and hold the lever 32 m a definite position.

It often happens, especially in dusty and sooty workshops, that the valves get dirty and do not accurately fit their seatings. To avoid evil results from this cause, it will be advisable that all the air-passages in and out should terminate in-a common air-chamber, so that the same air may be repeatedly employed, anyloss being compensated for by a supply through a pipe leading to the open air and provided, if desired, with a filtering medium. This air-chamber should be large, so that the air may be maintained in a cool condition.

down the discharge-flap 41.

Owing to the high number of strokes and the circumstance that the workman must give his full attention to the block instead of to the gearing-lever, it may easily happen that the turning motion of the cock 24 in the position effecting the free connection of the cylinders 1 and 3 is effected just at the time when the plunger 2 is lowered. In this case a second filling of the pump-cylinder 3 is pressed in the ram-cylinder 1, whereby the air-pressure below the ram-plunger 2 becomes so high that the latter mlght push Besides, this high air-pressure opposes the following lowering of t e ram (in spite of the upper pressure action) to such a degree that the first blow is entirely without any effect, or

nearly so. Not until the excess of air-pressure is compensated does the hammer begin its regular action. In order to overcome this fault, a weighted discharge-valve 40 is provided, capable of bringing into communication the cylinder-chamber 4 (below the rampiston 2) with the atmosphere. This discharging-valve is preferably a globe-valve 40 under action of a spring 42, the charge of which may be varied by screwing up or The charge is regulated in such a manner that during the normal working of the hammer the pressure of air effecting the raising of the hammer is not able to open the valve, so that no loss neither of air nor pressure results.

When after the raising of the hammer a second filling of the air-cylinder has been pressed into the ram-cylinder, whereby the air-pressure in the latter is considerably augmented, this pressure will open the valve, the excess of air will discharge, and the hammer will act regularlyQ Instead of a sprin actuated valve 1 may employ a simple weighted safety-valve.

In 0 eration the iston 6 will be reciprocated y any suita 1e means-as, for instance, by means of a rod 50, jointed at 51 tothe piston-rod, said rod 50 being at its lower end jointed to a wristin'53 on a disk 54, mounted on one end of a ri -shaft 55, Whose opposite end carries belt p iilleys 56.

Assuming the arts to be in the osition seen in Fig. 4., wit the piston 6 at the limit of its u ward movement and the piston 2 at the limit of its downward movement, when the piston 6 descends the air below it will be compressed and all or only a art of such air (according to the osition of t e cock 24) will be forced into 0 linder 1 beneath the piston 2 and. raise t e latter. The descendi movement of the piston 6 forms a partia vacuum behind it, and the valve 11 will be opened to admit air into cylinder 3 as soon as the iston 6 has passed by the port leading from t e valve 11.

Upon the u ward movement of piston 6 the air will be awn from beneath the piston .2, part of it escaping to the open air and part entering cylinder 3, While the air above the piston 6 will be compressed and cause the piston 2 to descend, thus making its working or hammer stroke. In the upward movement of-piston 6 air will be drawn in beneath it throu h valve 11 as soon as the piston has passed t eport lead' from said valve In 112% the above manner t ammer-piston will be alternately raised and lowered.

Having now described the nature of-my said invention, what I claim is 1. In an apparatus of the character described, the combination with a hammer or ram cylinder, an air-pump cylinder, a iston working in each of said cylinders, an con-.

nections between the cylinders above and below the pistons therein, of an air-inlet valve arranged on the air-pump cylinder at such a point that the valve will be closed by the lowerin pump-piston about at the beginning of t e ralsmg motion of the hammerp1ston to prevent the drawing in of air durmg the luck raising motion whereby an aircushion elow the ram-piston is revented, a valve 24 in the lower connection etween the cylinders, an air-discharge, valve connected with the upper end of the pump-cylinder and adapted to ermit of theescape of air from above the giammeriston to the atmosphere, and a connection between the valve 1n the lower connection between the cylinders' and the said air-discharge valve, comprising a rod adapted to raisethe air-discharge valve, and a series of jointed levers one of which is connected with the valve 24 and adapted to be actuated thereby and another of said levers being adapted to actuate the said rod, all being arra ed and adapted for 006 eration whereby sai air-discharge valve an valve 24 will be operated simultaneously in the manner described.

-2. In an apparatus of the character described, the combination with a hammer or below the pistons therein, of an air-inlet 7 valve 24 in said connection openin toward the hammer-cylinder, said valve 24 aving a bore and an orifice 29 communicating w1th' said bore and the casing for said valve having orifices adapted to be placed in communication with the boreof the valve in the manner and for the purpose specified.

In testimon that I claim the foregoing as my invention have signed my name in presence of two subscribi witnesses. A

I Y -C NRAD PRUNER. Witnesses:

WILHELM BERGER, ALVESTO S. HooUn. 

